The Changi Airport Skytrain is a people mover system that connects Terminals 1, 2 and 3 at Singapore Changi Airport. Opened in 1990, it was the first auto-guided system in Asia. The Changi Airport Skytrain operates from 0500 to 0230 daily and operates at 1 to 2-minute intervals. Travel on the Skytrain is free and an inter-terminal journey takes about 90 seconds. All stations have platform screen doors, are air conditioned and have plasma displays indicating the arrival time of the next train.